Augmenting a pH Medical Study with Wearable Video for Treatment of GERD Thad Starner and Daniel Ashbrook College of Computing Georgia Institute of Technology Atlanta, GA 30332 {thad,anjiro}@cc.gatech.edu Abstract In this paper we present an augmentation to the wear- able computers typically used to determine if a patient is a candidate for surgery to correct problems associated with Gastroesophageal Reflux Disease (GERD). A wear- able camera was used by the first author while participat- ing in a 24–hour stomach acid pH study. After the study’s conclusion, an examination of the captured video and pH record revealed some results that allowed the first author to avoid many of the activities that result in symptoms related to GERD. 1 GERD and Medical Testing Gastroesophageal Reflux Disease is a medical condition that affects 2% of the adult population of the United States. GERD refers to the reflux of stomach acid into the esopha- gus and can lead to complications such as esophageal cancer and lung damage. The most common symptom of GERD is heartburn. Typical treatments for GERD include diet mod- ification and medication; however, for some patients these treatments may prove ineffective, and the patient may be evaluated for more drastic measures such as surgery. If surgery to correct GERD is considered an option, the patient usually undergoes a 24– or 48–hour pH study to measure the percentage of time that the patient is in reflux during normal daily activities. In the 24–hour study, a pH probe is inserted into the subject’s nose and lowered through the esophagus to a position above the stomach. Since the probe is attached to a line that is retained in the patient’s nose and throat, several pH sensors can be placed at vary- ing locations along the patient’s esophagus. The probe is attached to a wearable computer which records the patient’s pH levels for 24 hours. The patient typically uses the wear- able computer to record times of meals, periods spent in a supine position (e.g. sleeping), and occurrences of symp- toms. The first author suffered from severe and relatively un- common symptoms of GERD in 1999. Symptoms persisted for eight months and included uncontrolled vomiting, sud- den and severe weight loss, hoarseness, coughing, diarrhea, and anxiety after waking. Symptoms disappeared after cor- rective surgery in 2000, but resumed in 2003 in the form of uncontrolled retching. After a change in diet and treat- ment for a bacterial stomach infection, the symptoms again disappeared, and a pH study showed a low rate of reflux. Figure 1. Medtronic pH monitor and CharmIT Pro wearable computer with video camera. In 2004, the author’s symptoms appeared again to a lesser degree. A 24–hour pH study was performed. Two pH sensors were placed in the esophagus and readings were recorded by a Medtronic Function Diagnostics Polygram 98 (version 2.01) wearable computer. In addition, the subject wore a small camera mounted on his chest, facing forward. The subject attempted to work and perform normal activi- ties as much as possible during the study. The wearable camera, a Logitech QuickCam Pro 4000 (removed from its housing) was equipped with a wide– angle lens, and 160x120 images were captured and times- tamped by the patient’s CharmIT Pro wearable computer once per second. With JPEG compression, 160MB is re- quired to store the 86,400 images captured during the 24–